Questions tagged [units]
Use for questions about standards of measurement used for different types of quantities, and for conversions between units.
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Astropy units issue
hope you're all doing well.
I'm not very familiarized with AstroPy and I'm having a problem computing the conversion between angular momentum units.
If I define the ...
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How to calculate an infrared SED from the specific intensities?
I have values of total infrared fluxes (SED) in literature expressed in Jy (Jansky) for galaxies. I want to assure that my infrared radial profiles of the same galaxies in MJy/sr (and other in Jy/...
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Convert from Jy/beam km/s to W/m$^2$
I need to compare some ALMA observations of a protoplanetary disk to disk-integrated fluxes obtained from a model.
The ALMA observations are upper limits of non-detected spectral lines, where the RMS ...
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Flux Density Unit Conversion [closed]
I am confused how to convert from ${\rm cm^{-2}\,s^{-1}\,Å^{-1}}$ to ${\rm erg\,cm^{-2}\,s^{-1}\,Å^{-1}}$. How do I do that?
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Rayleighs units conversion
I have a question regarding the units conversion from photon counts on a detector to Rayleighs. I am pretty new to the subject but I would like to know more.
The problem is the following :
I know that ...
1
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1
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RA expressed in degrees
Using the Python package Skyfield I thought that I could get the RA expressed in degrees simply by doing ra.degrees, but I get the following message
this angle is usually expressed in hours, not ...
3
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1
answer
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Units and some equations
I'm a grad student and I feel like this is an extremely elementary question that I should know, but I admit that I don't. Occasionally in science I find myself solving an equation for some answer ...
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Mathamatica vs Sympy and Astropy to solve basic astronomy problems: solving linear equations and unit conversion
I realize this may be slightly off topic, but I also believe this is probably the best way to get an answer to my question:
What is the best combination of software packages / programming languages to ...
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Unit problem regards to proton
In a textbook, we have an example:
The density of matter in the interstellar medium is of order one
proton per ${\rm cm^3}$, then the total mass of the interstellar
medium is of order (The $10^6$ ...
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Converting from $\mathrm{W \: m^{-2}}$ to $\mathrm{Jy \: km \: s^{-1}}$
Suppose I observe a spectral line with rest frequency $\nu_0$ and integrated flux density $F = 10^{-26} \mathrm{W/m^2}$. Is the following line of reasoning correct?
$1 \: \mathrm{Jy} = 10^{-26} \: \...
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What does BJD-2450000 mean?
In different papers I've encountered time indications in BJD-2450000. I know that BJD stands for Barycentric Julian Date, but I don't understand the meaning of the suffix -2450000.
This is an example ...
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How to use spectral flux density data while using Planck's law giving spectral radiance?
I'm currently working on a fun project in my free time where I'm trying to calculate the temperature, among other things, of stars based on their spectra. Since I have essentially no prior experience ...
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Flux density from brightness map
This is a naive question. I have a temperature map of radio emission at 1420 MHz, in Kelvin. I want to extract the flux density (in Janskys) from an extended region of this map.
Is the flux density ($...
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'Little h' usage in cosmological simulations
I am running a cosmological simulation and am having some trouble putting things into code units. The physical distance units in my simulation are in terms of $\text{Mpc/h}$, where $h$ is the ...
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Units confusion while calculating flux of a star using distance and luminosity, Python
I am trying to calculate the flux of various stars in Python. I am using the information from a database containing all stars in Hipparcos, Yale Bright Star, and Gliese catalogs (almost 120,000 stars)....
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